If the equation x4−3x3+mx2−7x+3=0 has four positive real roots. Then,
The given equation is x4−3x3+mx2−7x+3=0
According to the relation between roots and coefficients of higher degree equations,
Sum of the roots taken two at a time
∑αβ=m
Since all the roots are positive real numbers
m should also be positive
So, m > 0.